The urine excretion of creatinine (CRE), 3-methylhistidine (3MH), and hydroxyproline (OHP) were investigated as indices of muscle damage associated with exercise-induced delayed muscle soreness (DMS). Subjects (n = 28) maintained meat-free diets for six days. Twenty-four hour urine volumes were obtained from each subject on day four (D4), day five (D5), and day six (D6). On D5 the exercise treatment was administered. Nine subjects (Group 1) performed nine weight lifting manuevers for the upper and lower body. Three sets of repetitions were performed at each of exercise, however, the exercises were done in a circuit thus allowing a 20 minute rest before an exercise was repeated. Eleven subjects (Group 2) performed only the upper body exercises (5) with all sets (3) completed at one exercise before the subject moved on to the next exercise. Eight subjects (Group 3) served as controls and avoided unaccustomed work during the test period.Fat free weight was determined for each subject and estimates of daily protein and caloric intakes were recorded. Muscular soreness was rated by each subject prior to exercise (D4), 24 hours post-exercise (D5), and 48 hours post-exercise (D6). Urine volumes were analyzed for CRE, 3MH, and OHP content. MANOVA for repeated measures on DMS, CRE, 3MH, and OHP were performed.Results showed significant differences in DMS on D4 and the two post-exercise days. Upper body soreness ratings on D6 were significantly greater for Group 2 than Group 1. The urine metabolites were statistically different for groups with Group 2 having the lowest excretion values. The changes in 3MH, OHP, and CRE were not statistically different for the three days. This was true for the absolute values of the metabolites and the values adjusted for fat free weight, daily diet variables, and CRE excretion.It was concluded, based on the CRE, 3MH, and OHP excretions, that DMS is not related to muscle damage. DMS may be related to fatigue, based on the degree and duration of soreness experienced by Group 2 compared to Group 1. It was also concluded that circuit training may be a preferred method of weight training to minimize delayed soreness in persons initiating a training program.